The CO-adsorbate electrooxidation on ruthenium cluster-like materials

The electrochemical response and electrode potential-dependent infrared spectra for CO-adsorbate oxidation on unsupported ruthenium cluster-like material (Rux), prepared in two organic solvents: (xylene (Xyl), and 1,2-dichlorobenzene (Dcb)) from tris–ruthenium dodecacarbonyl decomposition, are reported. In spite of a similar particle size (2 nm) of the materials, the interfacial pseudo-capacitance of Rux(Xyl) is ca. four times higher than that of Rux(Dcb). Wide angle X-ray spectroscopy (WAXS) analysis on Rux(Xyl) and Rux(Dcb) nanoparticles revealed a high degree of structural disorder on Rux(Xyl) (J. Phys. Chem. B 105 (2001) 5238). The surface state of Rux(Xyl) and Rux(Dcb) used to oxidize CO, to form oxide-like (RuxOy) species, and used to recover the metallic nanoprecursor (under hydrogen annealing) can be inherently attributed to the degree of surface atom disorder. The CO absorption bands recorded on both types of surfaces are linear in nature and have apparently similar behavior to that observed on massive or well-defined ruthenium electrode surfaces.